AOS (Animate On Scroll)

This code will create a div with an AOS instance and set its anchor location to "top-center".

<link href="https://unpkg.com/aos@2.3.1/dist/aos.css" rel="stylesheet">
<script src="https://unpkg.com/aos@2.3.1/dist/aos.js"></script>

<div data-aos="fade-up" data-aos-anchor-placement="top-center" id="testas">AAA</div>

<script>
AOS.init({
  once: true,
  duration: 750,
})
</script>